In 2010, an estimated 60% of the 36 million people with dementia in the world live in low middle income countries (LMIC), increasing to 71% of 115 million by 2050. This is alarming because LMIC lack the social and healthcare policies to meet the challenges of caring for their rapidly growing number of people with dementia. In North Africa and the Middle East, research activities into dementia are generally lacking and no reliable database exists to help promote and guide policy development. Knowledge about dementia prevalence and incidence, risk and protective factors specific to the ethnic groups of the region is scarce. This study is part of 10/66 Dementia Research Group (DRG), an international network of researchers who have successfully carried out population-based studies onto dementia in 11 LMIC during the last decade. The long-term goal is to conduct a longitudinal community-based cohort study comprising 2500 people older than 65 years randomly selected from all regions of Lebanon to provide knowledge about the incidence, prevalence, risk and protective factors specific to the Lebanese population, and the barriers to treatment and care for people with dementia in Lebanon. The specific aims of this exploratory study are: 1) To validate the 10/66 DRG one-stage dementia diagnostic package in Arabic and 2) To carry out a pilot study in two governorates in Lebanon: Beirut and Nabatieh. The study will be conducted by the Department of Epidemiology and Population Health, American University of Beirut (AUB), Lebanon, in collaboration with the Division of Neurology, AUB Medical Center; The Lebanese Alzheimer's Association, the Danish Dementia Research Center (DDRC) in Copenhagen, Denmark; and the Institute of Psychiatry, King's College London, UK. The DDRC and the Institute of Psychiatry, King's College London, will build capacity for the Lebanese counterparts in dementia diagnostics and epidemiology as well as 10/66 DRG methodology to initiate this exploratory study and take the lead in follow-up studies. To achieve the proposed aims: 1) The validation study will include 150 participants with dementia diagnosed by experienced clinicians and 150 age-, gender-, and education-matched controls. Trained interviewers blinded to the participants' cognitive status will administer the 10/66 diagnostic package to the participants. Sensitivity and specificity of the 10/66 dementia diagnostic package will be calculated. 2) Once the diagnostic instrument is validated, a pilot study including 492 participants in Beirut and Nabatieh governorates will be carried out to field test the instrument, assess feasibility of the subsequent cohort study, and generate preliminary data about dementia prevalence.